Improvement in pianos



-C. BUERNER.

Pianos.

N0.lv54,447, Patented ug.25,1874.

Titnsses UNITED STATES PATENT OEEIGE.

CHRISTIAN BOERNER, OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT IN PlANos.

Specification forming part of Letters Patent No. 154,447, dated August25, 1874; application tiled May (i, 1874.

To all whom it may concern:

Be it known that I, CHRISTIAN BOERNER, of San Francisco city and county,State of California, have invented an Improvement in Upright Pianos andI do hereby declare the following description and accompanying drawingsare sufficient to enable any person skilled in the art or science towhich it most nearly appertains to make and use my said invention orimprovement without further invention or experiment.

My invention relates to certain improvements in the construction ofupright pianos, by which I am enabled to so secure the iron frame to thewooden frame of the piano that I can make a larger' sounding-boardwithin a certain sized piano; and it further consists in a novel methodof securing the sound-board within the piano so that it can be adjustedwith relation to the strin and bridges, and secure in a greaterdegreethe singing-tone, so desirable in this instrument. The wrestplank isalso secured in a novel manner to prevent it from tipping over orspringing.

Referring to the accompanying drawings for a more complete explanationof my invention, Figure l is a front view of my improved piano. Fig. 2is a back elevation.

A is the piano-frame, made with the timbers B inside ot' it, to whichthe iron frame C is to be secured.

In the ordinary construction of this class of pianos these timbers areplaced back of the iron frame, and as they are together from three andone-half to t'our inches thick, it will be seen that the sound-board,which must in all cases be placed behind the iron frame, will be just somuch shorter and less available.

The timbers B being in front of the iron frame in my piano, thislatterris screwed to the timbers by screws, and is very solid.

The wrest-plank D, which holds the tuningpins, is ordinarily glued intoits place, and also .to vertical timbers, to which the soundboard isglued 5 but in my improvement this wrest-plank is screwed to the timbersB from behind, and an iron plate, E, is strongly screwed upon the top ofthe plank to prevent it from springing in the middle, or bending towardthe front when the stra-n of the strings is upon it. The iron frame haspoints or lugs F extending upward from its top, and these lugs enter thelower part of the wrest-plank and prevent it from being forced back bythe strain of the strings across the bridge.

Another advantage possessed by my wrestplank is, that it is free to movedownward slightly, and altogether by the strain upon the strings;whereas, if it is glued to timbers at the back, any such strain has .atendency to split it.

Instead of employing vertical timbers behind the sound-board G, to whichit and the wrest-plank are glued, I dispense with them entirely, andsecure my sound-board directly to the iron frame C by means ofscrew-bolts H. Nuts I serve to draw the sound-board down toward the ironframe more or less, and thus adjust it so that the bridge J, over whichthe strings pass, can be brought to bear against them with a pressurejust calculated to bring out the best tones; and if at any future timethe bridge should not bear quite hard enough, by reason of thesound-board springing, it will be easy to set the latter up toward thestrings a little, and thus the tone is always preserved at its best,which cannot be done where the sound-board is permanently fixed to theupright timbers, as before described.

By dispensing with these timbers I am enabled to make my instrumentconsiderably lighter than by any other construction.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

1. The wrest-plank D, the top metal plate E, and the legs F on the metalframe C, combined and arranged substantially as described, and for thepurpose set forth.

2. In a piano, the metal frame C, in combination with the wrest-plank Dand soundboard G, arranged together, relatively, as shown and described,for the purpose set forth.

In witness whereotl hereunto set my hand and seal.

CHRISTIAN BOERNER.

Witnesses:

JNO. L. BOONE, C. M. RICHARDSON.

